TWI830683B - A film structure for electric field guided photoresist patterning process - Google Patents

Abstract

Methods and apparatuses for minimizing line edge/width roughness in lines formed by photolithography are provided. In one example, a method of processing a substrate includes applying a photoresist layer comprising a photoacid generator to on a multi-layer disposed on a substrate, wherein the multi-layer comprises an underlayer formed from an organic material, inorganic material, or a mixture of organic and inorganic materials, exposing a first portion of the photoresist layer unprotected by a photomask to a radiation light in a lithographic exposure process, and applying an electric field or a magnetic field to alter movement of photoacid generated from the photoacid generator substantially in a vertical direction.

Description

Film structures for electric field-guided photoresist patterning processes

The present disclosure relates generally to methods and apparatus for processing substrates, and more particularly to methods and apparatus for enhanced photoresist profile control.

Integrated circuits have evolved into complex devices that can include millions of components (such as transistors, capacitors, and resistors) on a single chip. Photolithography can be used to form components on the wafer. Generally speaking, the photolithography process involves several basic stages. Initially, a photoresist layer is formed on the substrate. The photoresist layer can be formed by, for example, spin coating. The photoresist layer may include a resist resin and a photoacid generator. After exposure to electromagnetic radiation in subsequent exposure stages, the photoacid generator changes the solubility of the photoresist during the development process. The electromagnetic radiation may be of any suitable wavelength, such as wavelengths in the extreme ultraviolet region. The electromagnetic radiation can come from any suitable source, such as a 193 nm ArF laser, electron beam, ion beam, or other sources. Excess solvent can then be removed in a pre-exposure bake process.

During the exposure stage, a photomask or master mask may be used to selectively expose certain areas of the photoresist layer disposed on the substrate to electromagnetic radiation. Other exposure methods may be maskless exposure methods. Exposure to light can decompose the photoacid generator, which generates acid and creates latent acid images in the resist resin. After exposure, the substrate can be heated in a post-exposure bake process. During the post-exposure bake process, the acid generated by the photoacid generator reacts with the resist resin in the photoresist layer, thereby changing the resist solubility of the photoresist layer during the subsequent development process.

After the post-exposure bake, the substrate (especially the photoresist layer) can be developed and rinsed. After development and rinsing, a patterned photoresist layer is then formed on the substrate, as shown in FIG. 1 . FIG. 1 depicts an exemplary top cross-sectional view of a substrate 100 having a patterned photoresist layer 104 disposed over a target material 102 to be etched. After the development and rinse process, openings 106 are defined between the patterned photoresist layers 104 , thereby exposing the underlying target material 102 for etching to transfer features to the target material 102 . However, inaccurate control or low resolution of the lithography exposure process may result in poor critical dimensions of the photoresist layer 104 , resulting in unacceptable line width roughness (LWR) 108 . Also, during the exposure process, the acid generated by the photoacid generator (as shown in Figure 1) may randomly diffuse into any area (including the undesired area protected by the mask), so in the pattern The polished photoresist layer 104 produces undesirable burrs or rough contours 150 at the edges or interfaces where it meets the openings 106 . Large line width roughness (LWR) 108 and undesirable burr profiles 150 of the photoresist layer 104 may cause inaccurate feature transfer to the target material 102 and thus ultimately lead to device failure or yield loss.

Therefore, methods and apparatus are needed to control line width roughness (LWR) and enhance resolution and dose sensitivity in order to obtain patterned photoresist layers with required critical dimensions.

Embodiments of the present disclosure include a method for forming a film structure to efficiently control acid from a photoacid generator in a photoresist layer during an exposure process or a pre-exposure bake process or a post-exposure bake process. Distribution and diffusion. In one example, a device structure includes: a film structure disposed on a substrate; and a plurality of openings formed in the film structure, wherein the openings formed across the substrate have a critical threshold between about 1 nm and 2 nm. Scale uniformity.

In another embodiment, a method of treating a substrate includes applying a photoresist layer including a photoacid generator onto a plurality of layers disposed on the substrate, wherein the plurality of layers includes an organic material, an inorganic material, or an organic material. an underlying layer formed from a mixture of materials and inorganic materials; exposing a first portion of the photoresist layer not protected by a photomask to radiant light during a lithography exposure process; and applying an electric or magnetic field to substantially vertical The movement of the photoacid generated by the photoacid generator is changed in the direction.

In yet another embodiment, a method of processing a substrate includes the following steps: coating a photoresist layer on an underlying layer disposed on the substrate; and removing portions of the photoresist layer that are not protected by a photomask during a photolithographic etching exposure process. exposing a first portion to radiant light; performing a baking process on the photoresist layer and the underlying layer; and applying an electric or magnetic field while performing the baking process.

This application provides a method for enhancing profile control of a photoresist layer formed by photolithographic etching. The diffusion of acid generated by the photoacid generator during the post-exposure bake process, which causes line edge/line width roughness, can be mitigated by utilizing a film structure disposed beneath the photoresist layer as disclosed herein. The application of an electric field controls the diffusion and distribution of the acid generated by the photoacid generator in the photoresist layer and the underlying layer in the film structure disposed below the photoresist layer, thereby preventing line edge/line width roughness caused by random diffusion. . Disclosed herein are methods for forming film structures disposed beneath photoresist layers used to control acid distribution and diffusion as described above.

Figure 2 is a schematic cross-sectional view of an apparatus for processing a substrate, according to one embodiment. As shown in the embodiment of Figure 2, the apparatus may be in the form of a vacuum processing chamber 200. In other embodiments, processing chamber 200 may not be coupled to a vacuum source.

Processing chamber 200 may be a stand-alone processing chamber. Alternatively, the processing chamber 200 may be part of a processing system (eg, an inline processing system, a cluster processing system, or a rail processing system, as appropriate). Processing chamber 200 is described in detail below, and may be used for pre-exposure bakes, post-exposure bakes, and/or other processing steps.

Processing chamber 200 includes chamber walls 202, electrode assembly 216, and substrate support assembly 238. Chamber wall 202 includes side walls 206, lid assembly 210, and bottom 208. Chamber wall 202 partially encloses processing volume 212. Access to the processing volume 212 is through a substrate transfer port (not shown) configured to facilitate movement of the substrate 240 into and out of the processing chamber 200 . In embodiments where processing chamber 200 is part of a processing system, substrate transfer ports may allow substrates 240 to be transferred into and out of an adjacent transfer chamber.

Pumping port 214 may optionally be provided through one of lid assembly 210, sidewalls 206, or bottom 208 of process chamber 200 to couple process volume 212 to the exhaust port. The exhaust port couples pumping port 214 to various vacuum pumping elements, such as a vacuum pump. The pumping element can reduce the pressure of the processing volume 212 and move any gases and/or process by-products out of the processing chamber 200 . The processing chamber 200 may be coupled to one or more supply sources 204 for delivering one or more source compounds into the processing volume 212 .

A substrate support assembly 238 is centrally located within the processing chamber 200 . Substrate support assembly 238 supports substrate 240 during processing. The substrate support assembly 238 may include a body 224 that encloses at least one embedded heater 232 . In some embodiments, substrate support assembly 238 may be an electrostatic chuck. A heater 232 (eg, a resistive member) is provided in the substrate support assembly 238 . The heater 232 controllably heats the substrate support assembly 238 and the substrate 240 positioned on the substrate support assembly to a predetermined temperature. The heater 232 is configured to quickly increase the temperature of the substrate 240 and to accurately control the temperature of the substrate 240 . In some embodiments, heater 232 is connected to and controlled by power source 274 . Power supply 274 may alternatively or additionally apply power to substrate support assembly 238 . Power supply 274 may be configured similarly to power supply 270, discussed below. Also, note that the heater 232 may be positioned from other locations within the processing chamber 200 (e.g., from the chamber walls, chamber liner, edge ring surrounding the substrate, chamber top wall, etc.) The base plate 240 on the base plate support assembly 238 provides thermal energy.

In some embodiments, substrate support assembly 238 may be configured to rotate. In some embodiments, substrate support assembly 238 is configured to rotate about the z-axis. The substrate support assembly 238 may be configured to rotate continuously or constantly, or the substrate support assembly 238 may be configured to rotate in a stepwise or indexed manner. For example, the substrate support assembly 238 may rotate a predetermined amount, such as 90°, 180°, or 270°, and then may stop rotating for a predetermined amount of time.

Generally speaking, the substrate support component 238 has a first surface 234 and a second surface 226 . First surface 234 is opposite second surface 226 . First surface 234 is configured to support substrate 240 . The second surface 226 has a rod 242 coupled thereto. Substrate 240 may be any type of substrate, such as a dielectric substrate, a glass substrate, a semiconductor substrate, or a conductive substrate. Substrate 240 may have a layer of material 245 disposed thereon. Material layer 245 may be any desired layer. In other embodiments, substrate 240 may have more than one material layer 245. The substrate 240 also has a photoresist layer 250 disposed over the material layer 245 . The substrate 240 has previously been exposed to electromagnetic radiation during the exposure phase of the photolithography process. The photoresist layer 250 has latent image lines 255 formed therein by the exposure stage. Latent image lines 255 may be substantially parallel. In other embodiments, latent image lines 255 may not be substantially parallel. Also, as shown, the first surface 234 of the substrate support assembly 238 is separated from the electrode assembly 216 by a distance d in the z direction. Rod 242 is coupled to a lift system (not shown) for moving substrate support assembly 238 between an elevated processing position (as shown) and a lowered substrate transfer position. The lifting system can accurately and precisely control the position of the substrate 240 in the z direction. In some embodiments, the lifting system may also be configured to move the substrate 240 in the x-direction, the y-direction, or both the x-direction and the y-direction. Rod 242 additionally provides conduit for electrical and thermocouple leads between substrate support assembly 238 and other components of processing chamber 200 . Bellows 246 is coupled to substrate support assembly 238 to provide a vacuum seal between processing volume 212 and the atmosphere outside processing chamber 200 and to facilitate movement of substrate support assembly 238 in the z-direction.

Lid assembly 210 may optionally include an inlet 280 through which gas provided by supply 204 may enter processing chamber 200 . The supply 204 may optionally controllably pressurize the treatment volume 212 with a gas such as nitrogen, argon, helium, other gases, or combinations thereof. Gas from supply 204 may create a controlled environment within processing chamber 200 . An actuator 290 may optionally be coupled between the cap assembly 210 and the electrode assembly 216 . Actuator 290 is configured to move electrode assembly 216 in one or more of the x, y, and z directions. The x and y directions are referred to herein as lateral directions or scales. Actuator 290 allows electrode assembly 216 to scan the surface of substrate 240 . The actuator 290 also allows the distance d to be adjusted. In some embodiments, electrode assembly 216 is coupled to cover assembly 210 via a fixed rod (not shown). In other embodiments, the electrode assembly 216 may be coupled to the interior of the bottom 208 of the processing chamber 200 , to the second surface 226 of the substrate support assembly 238 , or to the rod 242 . In yet other embodiments, electrode assembly 216 may be embedded between first surface 234 and second surface 226 of substrate support assembly 238 .

The electrode assembly 216 includes at least a first electrode 258 and a second electrode 260 . As shown, first electrode 258 is coupled to power source 270 and second electrode 260 is coupled to optional power source 275 . In other embodiments, one of the first electrode 258 and the second electrode 260 may be coupled to a power source, and the other electrode may be coupled to ground. In some embodiments, the first electrode 258 and the second electrode 260 are coupled to ground, and the power supply 274 delivering power to the substrate support is a bipolar power supply that switches between positive and negative biases. In some embodiments, power source 270 or power source 275 may be coupled to both first electrode 258 and second electrode 260 . In other embodiments, power supply 270 or power supply 275 may be coupled to first electrode 258 , second electrode 260 , and substrate support assembly 238 . In such embodiments, the pulse delay of each of first electrode 258, second electrode 260, and substrate support assembly 238 may be different. Electrode assembly 216 may be configured to generate an electric field parallel to the x-y plane defined by the first surface of substrate support assembly 238 . For example, electrode assembly 216 may be configured to generate an electric field in one of the y direction, the x direction, or other directions in the x-y plane.

Power supply 270 and power supply 275 are configured to supply, for example, between about 500 V and about 100 kV to electrode assembly 216 to generate an electric field having a strength between about 0.1 Mv/m and about 100 MV/m. In some embodiments, power supply 274 may also be configured to provide power to electrode assembly 216 . In some embodiments, any or all of power supply 270, power supply 274, or power supply 275 are pulsed direct current (DC) power supplies. Pulsed DC waves can come from half-wave rectifiers or full-wave rectifiers. DC power can have a frequency between approximately 10 Hz and 1 MHz. The duty cycle of the pulsed DC power supply may be between about 5% and about 95%, such as between about 20% and about 60%. In some embodiments, the duty cycle of the pulsed DC power supply may be between about 20% and about 40%. In other embodiments, the pulsed DC power supply may have a duty cycle of approximately 60%. The rise and fall times of the pulsed DC power supply may be between about 1 ns and about 1000 ns, for example, between about 10 ns and about 500 ns. In other embodiments, the rise and fall times of the pulsed DC power supply may be between about 10 ns and about 100 ns. In some embodiments, the rise and fall times of the pulsed DC power supply may be approximately 500 ns. In some embodiments, any or all of power supply 270, power supply 274, and power supply 275 are AC power supplies. In other embodiments, any or all of power supply 270, power supply 274, and power supply 275 are DC power supplies.

In some embodiments, any or all of power supply 270, power supply 274, and power supply 275 may use a DC offset. The DC offset may be, for example, between about 0% and about 75% of the applied voltage, for example, between about 5% and about 60% of the applied voltage. In some embodiments, the first electrode 258 and the second electrode 260 are negatively pulsed, and the substrate support assembly 238 is also negatively pulsed. In these embodiments, the first and second electrodes 258, 260 and the substrate support assembly 238 are synchronized but offset in time. For example, the first electrode 258 may be in the "one" state and the substrate support assembly 238 is in the "zero" state, then the substrate support assembly 238 is in the one state and the first electrode 258 is in the zero state.

Electrode assembly 216 spans approximately the width of substrate support assembly 238 . In other embodiments, the width of electrode assembly 216 may be smaller than the width of substrate support assembly 238 . For example, electrode assembly 216 may span between about 10% and about 80% (eg, about 20% and about 40%) of the width of substrate support assembly 238 . In embodiments in which electrode assembly 216 is not wider than substrate support assembly 238 , actuator 290 may scan electrode assembly 216 across the surface of substrate 240 positioned on first surface 234 of substrate support assembly 238 . For example, actuator 290 may scan such that electrode assembly 216 scans the entire surface of substrate 240 . In other embodiments, actuator 290 may scan only certain portions of substrate 240. Alternatively, substrate support assembly 238 may scan underneath electrode assembly 216 .

In some embodiments, one or more magnets 296 may be positioned in the processing chamber 200 . In the embodiment shown in FIG. 1 , magnet 296 is coupled to the interior surface of sidewall 206 . In other embodiments, the magnet 296 may be positioned in other locations within the processing chamber 200 or outside of the processing chamber 200 . Magnet 296 may be a permanent magnet or an electromagnet, for example. Representative permanent magnets include ceramic magnets and rare earth magnets. In embodiments where magnet 296 includes an electromagnet, magnet 296 may be coupled to a power source (not shown). Magnet 296 is configured to generate a magnetic field in a direction that is perpendicular or parallel to the direction of the electric field lines generated by electrode assembly 216 at first surface 234 of substrate support assembly 238 . For example, magnet 296 may be configured to generate a magnetic field in the x-direction when the electric field generated by electrode assembly 216 is in the y-direction. The magnetic field drives the charged species 355 (shown in FIG. 3 ) and polarized species (not shown in FIG. 3 ) generated by the photoacid generator in the photoresist layer 250 in a direction perpendicular to the magnetic field (eg, a direction parallel to the latent image line 255 ). Shows). By driving the charged material 355 and the polarized material in a direction parallel to the latent image line 255, line roughness can be reduced. The uniform directional movement of the charged substance 355 and the polarized substance is indicated by the bidirectional arrow 370 in FIG. 3 . In contrast, when no magnetic field is applied, the charged species 355 and polarized species can move randomly, as shown by arrows 370'.

Continuing to refer to FIG. 3 , the electrode assembly 216 includes at least a first electrode 258 and a second electrode 260 . The first electrode 258 includes a first terminal 310, a first support structure 330, and one or more antennas 320. The second electrode 260 includes a second terminal 311, a second support structure 331, and one or more antennas 321. The first terminal 310 of the first electrode 258, the first support structure 330, and the one or more antennas 320 may form a single body. Alternatively, first electrode 258 may include separate parts that may be coupled together. For example, one or more antennas 320 may be removable from the first support structure 330 . The second electrode 260 may similarly be a unitary body or comprise a separate removable element. The first electrode 258 and the second electrode 260 may be fabricated by any suitable technology. For example, the first electrode 258 and the second electrode 260 can be manufactured by machining, casting, or additive manufacturing.

The first support structure 330 may be made of conductive material, such as metal. For example, the first support structure 330 may be made of silicon, polycrystalline silicon, silicon carbide, molybdenum, aluminum, copper, graphite, silver, platinum, gold, palladium, zinc, other materials, or mixtures of the foregoing. The first support structure 330 may have any desired dimensions. For example, the length L of the first support structure 330 may be between about 25 mm and about 450 mm, such as between about 100 mm and about 300 mm. In some embodiments, the first support structure 330 has a length L approximately equal to the diameter of a standard semiconductor substrate. In other embodiments, the first support structure 330 has a length L that is greater or less than the diameter of a standard semiconductor substrate. For example, in various representative embodiments, the length L of the first support structure 330 may be about 25 mm, about 51 mm, about 76 mm, about 100 mm, about 150 mm, about 200 mm, about 300 mm, or Approximately 450 mm. The width W of the first support structure 330 may be between about 2 mm and about 25 mm. In other embodiments, the width W of the first support structure 330 is less than about 2 mm. In other embodiments, the width W of the first support structure 330 is greater than about 25 mm. The thickness of the first support structure 330 may be between about 1 mm and about 10 mm, such as between about 2 mm and about 8 mm, such as about 5 mm. In some embodiments, the first support structure 330 may be square, cylindrical, rectangular, oval, rod-shaped, or other shapes. Embodiments with curved outer surfaces can avoid arcing.

The support structure 330 may be made of the same material as the second support structure 331 . The range of dimensions suitable for the first support structure 330 is also suitable for the second support structure 331 . In some embodiments, the first support structure 330 and the second support structure 331 are made of the same material. In other embodiments, the first support structure 330 and the second support structure 331 are made of different materials. The length L, width W, and thickness of the first support structure 330 and the second support structure 331 may be the same or different.

One or more antennas 320 of first electrode 258 may also be made of conductive materials. One or more antennas 320 may be made from the same material as the first support structure 330 . The one or more antennas 320 of the first electrode 258 may have any desired dimensions. For example, the length L1 of the one or more antennas 320 may be between about 25 mm and about 450 mm, such as between about 100 mm and about 300 mm. In some embodiments, one or more antennas 320 have a length L1 that is approximately equal to the diameter of a standard substrate. In other embodiments, the length L1 of one or more antennas 320 may be between approximately 75% and 90% of the diameter of a standard substrate. The width W1 of the one or more antennas 320 may be between about 2 mm and about 25 mm. In other embodiments, the width W1 of one or more antennas 320 is less than about 2 mm. In other embodiments, the width W1 of one or more antennas 320 is greater than about 25 mm. The thickness of one or more antennas 320 may be between about 1 mm and about 10 mm, such as between about 2 mm and about 8 mm. One or more antennas 320 may have a square, rectangular, oval, circular, cylindrical, or another shaped cross-section. Embodiments with rounded outer surfaces avoid arcing.

Each of the antennas 320 may have the same dimensions. Alternatively, some of the one or more antennas 320 may have different dimensions than one or more of the other antennas 320 . For example, some of the one or more antennas 320 may have a different length L1 than one or more of the other antennas 320 . Each of one or more antennas 320 may be made from the same material. In other embodiments, some of the antennas 320 may be made of different materials than other antennas 320 .

Antenna 320 may be made from the same range of materials as antenna 320 . The range of dimensions suitable for antenna 320 is also suitable for antenna 321. In some embodiments, antenna 320 and antenna 321 are made of the same material. In other embodiments, the antenna 320 and the antenna 321 are made of different materials. The length L1, width W1, and thickness of the antenna 320 and the antenna 321 may be the same or different.

Antennas 320 may include between 1 and about 40 antennas 320 . For example, the antennas 320 may include between about 4 and about 40 antennas 320, such as between about 10 and about 20 antennas 320. In other embodiments, the antenna 320 may include more than 40 antennas 320 . In some embodiments, each of the antennas 320 may be substantially perpendicular to the first support structure 330 . For example, in embodiments where the first support structure 330 is straight, each antenna 320 may be substantially parallel to the first support structure 330 . Each of the antennas 320 may be substantially parallel to each of the other antennas 320 . Each of the antennas 321 may be similarly positioned relative to the support structure 331 and each other antenna 321 .

Each of the antennas 320 has a terminal 323. Each of the antennas 321 has a terminal 325. Distance C is defined between first support structure 330 and terminal 325 . Distance C' is defined between second support structure 331 and terminal 323 . Each of the distances C and C' may be between about 1 mm and about 10 mm. In other embodiments, distances C and C' may be less than about 1 mm or greater than about 10 mm. In some embodiments, distance C and distance C' are equal. In other embodiments, distance C and distance C' are different.

A distance A is defined between one of the antennas 321 and the facing surface of an adjacent one of the antennas 321 . Distance A' is defined between the facing surfaces of one antenna 320 and an adjacent one of the antennas 320 . The distances A and A' may be greater than approximately 6 mm. For example, the distances A and A' may be between about 6 mm and about 20 mm, such as between about 10 mm and about 15 mm. The distances A and A' between each adjacent antenna 321, 320 may be the same or different. For example, the distance A′ between the first antenna and the second antenna, the second antenna and the third antenna, and the third antenna and the fourth antenna in the one or more antennas 320 may be different. In other embodiments, distance A' may be the same.

A distance B is defined between the facing surfaces of one of the antennas 320 and an adjacent one of the antennas 321 . Distance B may, for example, be greater than approximately 1 mm. For example, distance B may be between approximately 2 mm and approximately 10 mm, such as between approximately 4 mm and approximately 6 mm. Each distance B can be the same, each distance B can be different, or some distances B can be the same and some distances B can be different. Adjusting the distance B allows easy control of the electric field strength.

The antennas 320, 321 may be oriented in a staggered arrangement over the photoresist layer 250. For example, the antenna 320 of the first electrode 258 and the antenna 321 of the second electrode 260 may be positioned such that at least one of the antennas 320 is positioned between two of the antennas 321 . Furthermore, at least one antenna 321 may be positioned between two of the antennas 320. In some embodiments, all but one of antennas 320 are positioned between two of antennas 321 . In such embodiments, all but one of antennas 321 may be positioned between two of antennas 320. In some embodiments, antenna 320 and antenna 321 may each have only one antenna.

In some embodiments, first electrode 258 has a first terminal 310 and second electrode 260 has a second terminal 311 . The first terminal 310 may be the contact between the first electrode 258 and the power source 270, the power source 275, or ground. The second terminal 311 may be a contact between the second electrode 260 and the power supply 270, the power supply 275, or ground. The first terminal 310 and the second terminal 311 are shown located at one end of the first electrode 258 and the second electrode 260 respectively. In other embodiments, the first terminal 310 and the second terminal 311 may be positioned at other locations on the first electrode 258 and the second electrode, respectively. The first terminal 310 and the second terminal 311 have different shapes and sizes from the first support structure 330 and the support structure 331 respectively. In other embodiments, the first terminal 310 and the second terminal 311 may have substantially the same shape and size as the first support structure 330 and the support structure 331 respectively.

In operation, voltage may be supplied to first terminal 310 , second terminal 311 , and/or substrate support assembly 238 from a power source (eg, power source 270 , power source 274 , or power source 275 ). The supplied voltage creates an electric field between each of the one or more antennas 320 and each of the one or more antennas 321 . The electric field will be strongest between one of the one or more antennas 320 and an adjacent one of the one or more antennas 321 . The staggered and aligned spatial relationship of antennas 320, 321 creates an electric field in a direction parallel to the plane defined by first surface 234 of substrate support assembly 238. Substrate 240 is positioned on first surface 234 such that latent image lines 255 are parallel to the electric field lines generated by electrode assembly 216 . Because the charged substance 355 is charged, the charged substance 355 is affected by the electric field. The electric field drives the charged species 355 generated by the photoacid generator in the photoresist layer 250 in the direction of the electric field. By driving charged material 355 in a direction parallel to latent image line 255, line edge roughness can be reduced. Uniform directional movement is shown by bidirectional arrow 370. In contrast, when no voltage is applied to the first terminal 310 or the second terminal 311, no electric field is generated in any particular direction to drive the charged substance 355. As a result, the charged material 355 can move randomly (as shown by arrow 370'), which may cause attention or line roughness.

Figure 4 depicts a film structure 404 disposed on a substrate 400 during a lithography exposure process. A photoresist layer 407 is provided on the film structure 404. Film structure 404 includes an underlying layer 405 disposed above hard mask layer 403 and disposed further above target layer 402 . Target layer 402 is then patterned to form the desired device features in target layer 402 . In one example, underlying layer 405 may be an organic material, an inorganic material, or a mixture of organic or inorganic materials. In embodiments where the underlying layer 405 is an organic material, the organic material may be a cross-linkable polymeric material that may be coated onto the substrate 400 via a spin coating process and then thermally cured, such that A photoresist layer 407 may be applied thereon. In embodiments where the underlying layer 405 is an inorganic material, the inorganic material may be a dielectric material formed by any suitable deposition technique (eg, CVD, ALD, PVD, spin-on coating, spray coating, etc.).

Underlying layer 405 serves as a planarization layer, anti-reflective coating, and/or photoacid direction control body, which can provide etch resistance and when transferring patterns into underlying hard mask layer 403 and target layer 402 Line edge roughness control. Patterned resist functionality from the underlying layer 405 may work with the underlying hard mask layer 403 during transfer of the resist process. In one example, the underlying layer 405 does not interact with the photoresist layer 407 and has no interfacial mixing and/or diffusion or cross-contamination with the photoresist layer 407 .

The underlying layer 405 includes one or more additives, such as acid agents (eg, photoacid generators (PAGs) or acid catalysts), alkaline agents, adhesion promoters, or photosensitive components. The one or more additives may be disposed in organic solvents or resins and/or inorganic matrix materials. Suitable examples of acid agents include photoacid generators (PAGs) and/or acid catalysts selected from the group consisting of sulfonic acids (e.g., p-toluenesulfonic acid, styrenesulfonic acid), sulfonates (e.g., p-toluenesulfonic acid), sulfonates (e.g., p- Pyridinium toluenesulfonate, pyridinium trifluoromethanesulfonate, pyridinium 3-nitrobenzenesulfonate), and mixtures of the above items. Suitable organic solvents may include homopolymers or higher polymers containing two or more repeating units and a polymeric backbone. Suitable examples of organic solvents include, but are not limited to, propylene glycol methyl ether acetate (PGMEA), ethyl lactate (EL), propylene glycol methyl ether (PGME), propylene glycol n-propyl ether (PnP), cyclohexanone, acetone, gamma-butyrate lactone (GBL), and mixtures of the above items.

In one example, underlying layer 405 provides active acids, alkalis, or ferrous/non-ferrous substances to assist in control during the lithography exposure process, pre-exposure bake process, or post-exposure bake process. The direction of photoacid flow from the upper photoresist layer 407.

Hard mask layer 403 may be an ARC layer made from the group consisting of silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, amorphous carbon, doped amorphous carbon, TEOS oxide , USG, SOG, silicone, oxide-containing materials, titanium nitride, titanium oxynitride, combinations of the above items, etc.

The photoresist layer 407 may be a positive photoresist and/or a negative photoresist capable of performing a chemical amplification reaction. Photoresist layer 407 is a polymeric organic material.

As discussed above, the electric field from electrode 116 and the magnetic field from magnet 296 may be applied during a lithography exposure process, a pre-exposure bake process, or a post-exposure bake process, particularly a post-exposure bake process. In the example depicted in Figure 4, electric and/or magnetic fields are applied during the lithography exposure process. During the lithography exposure process, optical radiation 412 is directed to the first region 408 of the photoresist layer 407 while the second region 406 of the photoresist layer 407 is protected by the photomask 410 . When a photoacid generator (PAG) is exposed to light radiation 412 (eg, UV light radiation), photoacid (shown as e ⁻ in FIG. 4 ) is generated in the exposed first region 408 of the photoresist layer 407 . However, in general, the movement of photoacid is generally random, and the photoacid distribution may be unevenly distributed in the first region 408 or may not have a clear boundary set between the first region 408 and the second region 406 . at the interface 430 on the plane between the two regions (interfacing with the second region 406), thereby causing a portion of the photoacid to drift and diffuse into the undesired second region 406 where photoacid is generated (as shown in arrow 422). As such, lateral photoacid movement (e.g., parallel to the flat surface of the substrate 400) that drifts into the second region 406 (as indicated by arrow 422) may cause line edge roughness, loss of resolution, and photoresist migration. , contour deformation, thus causing inaccurate feature transfer to the underlying target layer 402 and/or ultimately leading to component failure.

Although the examples discussed herein are shown as the movement of electrons from a photoacid, note that any suitable species (including charges, charged particles, photons, ions, electrons, or reactive species in any form) may also be present in the movement of electrons toward the photoacid. The resistive layer 407 has a similar effect when an electric field is applied.

By applying an electric field and/or a magnetic field to the photoresist layer 407, the distribution of photoacid in the exposed first region 408 can be efficiently controlled and constrained. For example, the electric field applied to the photoresist layer 407 can be substantially consistent with the flat surface of the substrate 400 in the vertical direction (e.g., indicated by arrows 416 and 420) with minimal lateral motion (e.g., the x-direction indicated by arrow 422). vertical y-direction) without diffusing into the adjacent second region 406. Generally speaking, the photoacid can have a certain polarity that can be affected by an electric or magnetic field applied thereto, thereby orienting the photoacid with certain directions, thus creating the desired directivity of the photoacid in the exposed first region 408 Move without crossing into the adjacent protected second area 406. In one example, the photoacid can be further controlled to directivity along a lateral plane (as indicated by arrow 414) with a longitudinal direction (e.g., the z-direction indicated by arrow 428), which is defined between 410) moves in the plane where the second region 406 of the protected photoresist layer 407 intersects so as to control the longitudinal distribution of the photoacid constrained in the exposed first region 408 without using the x-direction (as indicated by arrow 422) across into the second region 406 of the photoresist layer 407 . The magnetic field generated to the photoresist layer 407 can cause the electrons to circulate along certain magnetic field lines, such as a longitudinal direction (eg, the z direction indicated by arrow 428), to further control the photoacid with a desired three-dimensional distribution. The interaction between the magnetic and electric fields can optimize the photoacid trace along a certain path and constrain it in the exposed first region 408 as needed. Also, vertical photoacid movement is required to eliminate standing waves naturally generated by light exposure tools, thus enhancing exposure resolution. In one embodiment, an electric field having an intensity between about 0.1 MV/m and about 100 MV/m may be applied to the photoresist layer 407 during a lithography exposure process, a pre-bake process, or a post-bake process. To constrain the photoacid generated in the photoresist layer 407 in the vertical direction (eg, the y direction). In one embodiment, a magnetic field between 0.1 Tesla (T) and 10 Tesla (T) may be applied to the photoresist layer 407 during a lithography exposure process, a pre-bake process, or a post-bake process. and an electric field to confine the photoacid generated in the photoresist layer 407 in the longitudinal and vertical directions (eg, y and z directions), with minimal confinement in the lateral direction (eg, x direction). While combining a magnetic field with an electric field, the photoacid as produced can be further constrained to be distributed in a longitudinal direction (eg, in the direction indicated by arrow 428) along the interface within the exposed first region 408 430 remains in the first region 408 of the photoresist layer 407 in parallel.

Figure 5 depicts another profile of a photoacid distribution that can be controlled by utilizing electric fields, magnetic fields, or a combination thereof to specifically control photoacid located at certain regions during the post-exposure bake process. After the lithography exposure process, the exposed area 502 of the photoresist layer 407 has been chemically changed from the first area 408 as shown in FIG. 4 . After the photoresist layer 407 is exposed by lithography, a post-exposure bake process is then performed to cure the photoresist layer 407, including the exposed area 502 and the remaining areas in the photoresist layer 407 (such as those that were photomasked during the lithography exposure process). mode shielded area). During the post-exposure bake process, control of the photoacid from the underlying layer 405 is used in a manner that assists in distributing/moving the photoacid within the photoresist layer 407 in the desired direction (as indicated by arrow 506 in Figure 5). Acidic agent (such as photoacid), alkaline agent, or other suitable additives. Additives in the underlying layer 405 diffuse into the upper photoresist layer 504 during the post-exposure bake process (or even during the lithography exposure process), which helps improve the sensitivity of the photoresist layer 407 so that the photoresist layer is maintained 407 vertical profile. As a result, a substantially vertical profile can be obtained in the photoresist layer 407 after development and processing.

In one embodiment, additives (such as acid or photoacid, for example) from underlying layer 405 can be thermally driven upward (as indicated by arrow 506) during the post-exposure bake process so that efficient control Outline of photoresist layer 407. Furthermore, because the additive from the underlying layer 405 can be driven upward in a specific direction by an electric field, a magnetic field, or a combination of the above during the post-exposure bake process, the electrons provided from the additive can be controlled to move along a certain path. (For example, most of them are in the vertical direction toward the photoresist layer 407). By doing so, the desired vertical structures can be defined and constrained in the photoresist layer 407 as desired. Note that the examples of photoresist layer 407 depicted in Figures 4-5 are formed with straight edge profiles (eg, vertical sidewalls). However, the photoresist layer 407 may be contoured as desired with any desired shape, such as a tapered or flared opening.

After the post-exposure bake process, an anisotropic etch process or other suitable patterning/etching process may be performed to transfer features into underlying layer 405, hard mask layer 403, and target layer 402 as desired.

6 depicts a flow diagram of a method 600 for utilizing an underlying layer disposed beneath a photoresist layer to assist in controlling the photoresist during a lithographic etch exposure process or during a pre-exposure bake process or a post-exposure bake process. Photoacid distribution/diffusion in the layer. Method 600 begins at operation 602 by positioning a substrate (eg, substrate 400 described above) into a processing chamber (eg, processing chamber 200 depicted in FIGS. 2-3 ) with electrode assemblies and magnetic assemblies disposed therein. in the processing chamber.

At operation 604, after positioning the substrate 400, electric and/or magnetic fields (applied during the lithographic etch exposure process and/or post-exposure bake process) may be applied to the processing chamber individually or collectively to control the content of the photoresist layer. The photoacid moves, where an underlying layer is disposed beneath the photoresist layer. After applying an electric field and/or a magnetic field to the photoresist layer and the underlying layer disposed on the substrate individually or jointly, the generated photoacid can mainly move in the vertical direction, longitudinal direction, or circular direction instead of in the lateral direction. move in the direction. As a result of the assistance provided by the underlying layer disposed below the photoresist layer, photoacid movement in the photoresist layer can be efficiently controlled.

At operation 606, after the exposure process, a post-exposure bake process is performed to cure the photoresist layer and the underlying layer. During the baking process, energy (such as electrical energy, thermal energy, or other suitable energy) may also be provided to the underlying layer. In one example depicted herein, the energy is thermal energy provided to the substrate during the post-exposure bake process. Additives from the underlying layer can also help control the flow direction of the photoacid within the photoresist layer. By utilizing directivity control of photoacid distribution in predetermined paths with patterned photoresist layers, it is possible to achieve high resolution, dose sensitivity, resistance to line collapse and random failures, and minimal line edge roughness. the desired edge profile. In one example, critical dimensional uniformity (CDU) (eg, critical dimensional variation) can be reduced from typically 3 nm to 6 nm to as low as 1 nm to 2 nm or less by exploiting underlying layer structures. A uniformity improvement of about 50% to 600%. Line width roughness (LWR) can be reduced from typically 3 nm to 5 nm to as low as 1 nm to 2 nm or less, which is a roughness improvement of approximately 50% to 600%. Also, the distance between the first tip of the first trench and the second tip of the second trench can be reduced from typically 30 nm to 50 nm to as low as 10 nm to 20 nm. Moreover, some types of defects (such as rounding, misalignment, deformed contours, skewed sidewall contours) can also be effectively eliminated and reduced.

The previously described embodiments have many advantages, including the following. For example, embodiments disclosed herein can reduce or eliminate line edge/line width roughness at high resolution and sharp edge profiles. The above advantages are illustrative rather than restrictive. All embodiments do not necessarily have all advantages.

Although the above is directed to embodiments of the disclosure, other and additional embodiments of the disclosure may be devised without departing from the essential scope of the disclosure, and the scope of the disclosure is determined by what follows. Determined by the scope of the patent application.

100:Substrate 102:Target material 104: Photoresist layer 106:Open your mouth 108: Line width roughness (LWR) 150: Burr outline 200: Processing Chamber 202: Chamber wall 204:Supply source 206:Side wall 208: Bottom 210: Cover assembly 212: processing volume 214:Pumping port 216:Electrode assembly 224:Subject 226: Second surface 232:Heater 234:First surface 238:Substrate support assembly 240:Substrate 242:rod 245:Material layer 246: Bellows 250: Photoresist layer 255: latent image line 258:First electrode 260: Second electrode 270:Power supply 274:Power supply 275:Power supply 280:Entrance 290: Actuator 296:Magnet 310: First terminal 311: Second terminal 320:Antenna 321:Antenna 323:Terminal 325:Terminal 330:First support structure 331: Second support structure 355:Charged substances 370: Two-way arrow 400:Substrate 402: Target layer 403: Hard mask layer 404: Membrane structure 405:Underlying layer 406:Second area 407: Photoresist layer 408:First area 410:Photomask 412: Optical radiation 414:Arrow 416:arrow 420:Arrow 422:Arrow 428:arrow 430:Interface 502: Exposed area 504: Apply photoresist layer 506:arrow 600:Method 602: Operation 604: Operation 606: Operation 370':arrow A:Distance A':distance B:distance C: distance d: distance L: length L1:Length W: Width

A more detailed description of the disclosure briefly summarized above, and the manner in which the above-described features of the disclosure may be understood in detail, may be obtained by reference to the embodiments, some of which are illustrated in the accompanying drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this disclosure and are therefore not to be considered limiting of its scope, for the disclosure may admit to other equally effective embodiments.

1 depicts a top view of an exemplary structure of a patterned photoresist layer conventionally disposed on a substrate in the art;

Figure 2 is a schematic cross-sectional view of an apparatus for processing a substrate according to one embodiment;

Figure 3 is a top view of one embodiment of an electrode assembly disposed in the device of Figure 2;

Figure 4 depicts acid distribution control of a photoresist layer disposed on a film structure during an exposure process;

Figure 5 depicts acid distribution control of a photoresist layer on a film structure with a desired profile during a post-exposure bake process; and

Figure 6 is a flow chart of a method of controlling acid distribution of a photoresist layer during an exposure process.

To facilitate understanding, the same reference numbers have been used where possible to designate the same elements common throughout the drawings. Furthermore, elements of one embodiment may be advantageously adapted for use in other embodiments described herein.

Domestic storage information (please note in order of storage institution, date and number) without Overseas storage information (please note in order of storage country, institution, date, and number) without

400:Substrate 402: Target layer 403: Hard mask layer 404: Membrane structure 405:Underlying layer 406:Second area 407: Photoresist layer 408:First area 410:Photomask 412: Optical radiation 414:Arrow 416:arrow 420:Arrow 422:Arrow 428:arrow 430:Interface

Claims (20)

A component structure including: a substrate; and A multi-layer film structure is provided on a substrate. The multi-layer film structure includes: An underlying layer, the underlying layer includes an organic solvent and an acid agent, the acid agent is selected from the group consisting of: a sulfonic acid, a sulfonate salt, and a mixture of the above items; A photoresist layer, including a photoacid generator, is disposed on the underlying layer, and is configured to move in a substantially vertical direction when exposed to an electric field or a magnetic field. a photoacid generated by the photoacid generator; and A photomask is disposed on the photoresist layer, and the photomask is configured to expose a first portion of the photoresist layer that is not protected by the photomask to radiant light in a photolithography exposure process. The device structure of claim 1, wherein the photomask has a plurality of openings exposing the first portion of the photoresist layer. The device structure of claim 2, wherein the openings exposing the first portion of the photoresist layer have a critical dimension between about 1 nm and 2 nm. The device structure of claim 1, wherein the underlying layer further includes one or more additives in an organic polymer solvent. The device structure of claim 4, wherein the underlying layer further includes an additive, and the additive includes an alkali agent, a tackifier, a photosensitive component, or any combination of the above. The component structure of claim 4, wherein the organic polymer solvent is selected from the group consisting of: propylene glycol methyl ether acetate (PGMEA), ethyl lactate (EL), propylene glycol methyl ether (PGME), Propylene glycol n-propyl ether (PnP), cyclohexanone, acetone, γ-butyrolactone (GBL), and mixtures of the above items. The device structure of claim 1, wherein the multi-layer film structure further includes: a hard mask layer disposed below the underlying layer and above the substrate. The device structure of claim 7, wherein the hard mask layer is selected from the group consisting of: silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, amorphous carbon, doped amorphous Carbon, TEOS oxide, USG, SOG, silicone, oxide-containing materials, titanium nitride, titanium oxynitride, and combinations of the above. The device structure of claim 1, wherein the underlying layer is an organic material. A component structure including: a substrate; and A multi-layer film structure is provided on a substrate. The multi-layer film structure includes: An underlying layer, the underlying layer includes an organic solvent and an acid agent; A photoresist layer, including a photoacid generator, is disposed on the underlying layer, and is configured to move in a substantially vertical direction when exposed to an electric field or a magnetic field. A photoacid generated by the photoacid generator forms a plurality of openings in the multilayer film structure, and the plurality of openings have a line width roughness (LWR) between about 3 nm and about 5 nm. between nm; and A photomask is disposed on the photoresist layer, and the photomask is configured to expose a first portion of the photoresist layer that is not protected by the photomask to radiant light in a photolithography exposure process. The device structure of claim 10, wherein the photomask has a plurality of openings exposing the first portion of the photoresist layer. The device structure of claim 11, wherein the openings exposing the first portion of the photoresist layer have a critical dimension between about 1 nm and 2 nm. The device structure of claim 10, wherein the underlying layer further includes one or more additives in an organic polymer solvent. The component structure of claim 13, wherein the organic polymer solvent is selected from the group consisting of: propylene glycol methyl ether acetate (PGMEA), ethyl lactate (EL), propylene glycol methyl ether (PGME), Propylene glycol n-propyl ether (PnP), cyclohexanone, acetone, γ-butyrolactone (GBL), and mixtures of the above items. The device structure of claim 10, wherein the underlying layer further includes an additive, and the additive includes an alkali agent, a tackifier, a photosensitive component, or any combination of the above. The device structure of claim 10, wherein the multi-layer film structure further includes: a hard mask layer disposed below the underlying layer and above the substrate. The device structure of claim 16, wherein the hard mask layer is selected from the group consisting of: silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, amorphous carbon, doped amorphous Carbon, TEOS oxide, USG, SOG, silicone, oxide-containing materials, titanium nitride, titanium oxynitride, and combinations of the above. The device structure of claim 16, wherein the multi-layer film structure further includes a target layer disposed below the hard mask layer and above the substrate. The device structure of claim 10, wherein the underlying layer is an organic material. The device structure of claim 10, wherein the photoresist layer is a polymer organic material.

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